Strap tensioning tool



April 21, 1964 A. SHARKO STRAP TENSIONING Toor.

Filed Dec. 28, 1961 United States Patent O 3,129,723 STRAP TENSIONING T601,

Alexander Shar-ko, Montreal, Quebec, Canada, assignor, by mesne assignments, to FMC Corporation, San lose, Calif., a corporation of Delaware Filed Dec. 2S, 1961, Ser. No. 162,301 2 Claims. (Cl. 14h-93.2)

This invention relates to a tool for stretching or tensioning flexible straps about boxes, cartons, and other articles and more particularly to such a tool having means for cutting the strap to length after it has been secured about one or more articles.

It is an object of the invention to provide an improved strapping tool having a single operating lever which is selectively operable to tension the strap and cut the same to length.

Another object of the invention is to provide a strapping tool, having a single lever for tensioning and cutting the strap, which has a minimum number of parts.

A further object of the invention is to provide a tool of the type referred to which is adapted for use in a vertical position When strapping large boxes or cartons Where it would be diliicult or inconvenient tov rest the tool on a horizontal surface.

Other objects, features and advantages of the invention will become apparent as the description of a preferred embodhnent thereof proceeds.

Referring now to the drawing:

FIG. l is a perspective view showing the tool in operation;

FIG. 2 is a view partly in side elevation and partly in section, showing the operating mechanism of the tool; and

FIG. 3 is a plan view of the forward end of the tool.

The tool comprises a main body portion 16 and a rearwardly extending handle portion 11. The bottom of body portion 1li is preferably iiat to conform with a flat surface of the box or carton 12 which is to be strapped. In the drawing the tool is shown resting on a horizontal surface of the carton but, as will become apparent, it may be used with equal facility on a vertical surface. Secured to the body portion 1t) and tlush with the bottom thereof is a plate 13 which extends outwardly from the side of the body portion and has attached thereto a housing member 14, a portion of which is spaced above plate 13 far enough to permit a flexible at strap 15 to be placed between the housing and the plate. Housing 14 is cut away as shown to accommodate a strap gripping wedge 16. A pin 17 is secured to wedge 16 and ts slidably into a bore 18 in housing 14 and a spring 19 surrounding pin 17 urges the wedge rearwardly to engage a serrated surface thereof with the top of plate 13. A wedge releasing lever 2t) is pivotally mounted on a pin 21 and works within a slot 22 provided in housing member 14. Lever 20 has an end 23 lying in juxtaposition with an ear 24 extending upwardly from wedge 16 into the slot 22 and is provided with a thumb piece 25. When the operator is holding handle 11 in his right hand he may conveniently use his thumb to rock lever in a clockwise direction to thereby move wedge 16 toward the left against the action of spring 19. Due to engagement of pin 17 within bore 18, leftward movement of wedge 16 causes the lower serrated surface thereof to be lifted from engagement with plate 13 so that the strap may be inserted beneath the wedge.

Body portion 16 includes a side wall 26, spaced from and extending parallel to which is a wall forming member 27. A shaft 28 is rotatably mounted in walls 26 and 27 and extends beyond wall 26. The extended portion of shaft 2S has secured thereto or formed integrally therewith a drum or windlass 29 provided with slots 30 to facilitate easy attachment of a portion of the strap thereto, as will presently be explained. Keyed or xed to shaft 28 between walls 26 and 27 is a ratchet wheel 31 and rotatably or pivotally mounted on said shaft is an operating lever 32, the lower end of which is bifurcated to provide legs 33 and 34 which straddle the ratchet wheel. A pawl 35 is slidably mounted within lever 32 between the legs 33 and 34 and is urged into engagement with the teeth of ratchet wheel 31 by a spring 36. Pawl 35 and the teeth of ratchet wheel 31 are so shaped that counterclockwise movement of lever 32, as viewed in FIGS. 1 and 2, is effective to rotate the ratchet wheel and windlass 30, but during clockwise movement of the lever, the pawl rides over the teeth of the ratchet wheel without imparting rotation thereto. A spring pressed pawl 37 engages the teeth of ratchet wheel 31 to prevent retrograde rotation of the ratchet wheel during clockwise movement of lever 32.

Extending from side wall 26 parallel to windlass 30 is a strap guiding element 33 having a slot 39 therethrough for accommodating the strap. A cutter member 40 is rockably mounted in the strap guiding element and extends through wall 26. Said cutter member is semicylindrical where it is aligned with slot 39 and adjacent the inner side of wall 26 is provided with a collar 41, see FIG. 3. A coil spring 42 is secured at one end to collar 41 and at the other to a projection 43 of wall member 27 and said spring urges said cutter member to the position shown in FIG. l, wherein the flat side of the semicylindrical portion thereof is aligned with slot 39. A shoulder 44 of collar 41 engages body portion 10 to provide the desired positioning of the cutter member.

Collar 41 has a projection 45 which extends into the path of movement of a projection 46 of leg 34 of lever 32 and when said lever is rocked far enough in a clockwise direction, projection 46 contacts projection 45. Projections 45 and 46 thus constitute cooperating means which define a normal stopping position for the clockwise movement of lever 32. Movement of lever 32 past this normal stopping position is effective to rock cutter member 40 from the position shown in FIG. l to the position shown in FIG. 2 to cut the strap within slot 39.

In use, the strap is drawn from a supply such as a roll and passed about the object and the operator, while holding the tool by handle 11, uses his thumb to rock lever 21B to lift Wedge 16 from engagement with plate 13. The end portion of the strap is placed between plate 13 and wedge 16 so that the tip of the strap extends beyond the strap guiding element 3S and the operator then releases lever 2t) to permit spring 19 to engage the Wedge with the strap and grip the strap between said plate and wedge. A portion of the strap between the object and the supply roll is then slipped edgewise into slot 39 of strap guiding element 38 and into the lowermost slot of windlass 29. The strap is laid part way around the windlass and passed through the uppermost slot thereof so that the strap is then engaged with two parallel slots of the windlass and is not apt to slip. Lever 32 is then oscillated back and forth to rotate windlass 29 and wind the strap thereabout until the desired degree of strap tension is achieved. During tensioning, lever 32 is oscillated through what is termed in the claims a normal arc, that is tor say it is moved in a clockwise direction only far enough to bring the projection 46 of the lever into contact with projection 45 of cutter collar 41. Spring 42 is strong enough to make the operator aware of the contact between projections 45 and 46 so there is no danger of inadvertently operating the cutter during the tensioning operation. It is to be noted that the windlass is operated only during counterclockwise movement of lever 32 and that very little effort is required to move the lever clockwise so that the fact that the operator must exert eXtra force on the lever in a counterclockwise direction as the strap became tighter does not cause him to fail to notice the resistance offered by spring 42 when moving the lever clockwise, When the strap has reached the desired degree of tension, the overlapping portions thereof are secured together in front of strap guiding element 3S by suitable means, for example, by crimping a seal 47 thereabout in a well-known manner. During application of seal 47, the operator may release the tool even if it is in a vertical position against the side of a large carton and it will be held in position by wedge 16 gripping the strap between it and plate 13. When the seal has been applied, lever 32 is swung clockwise to an extreme position to rock cutter member 4t) and cause it to cut the strap.

Having thus described a preferred embodiment of the invention, what is claimed is:

l. A strap tensioning tool comprising gripping means for gripping an end portion of a iiexible strap, a slotted windlass for engaging another portion of the strap, a rotatably mounted shaft supporting said windlass, a ratchet wheel fixed to said shaft, a lever pivotally mounted on said shaft, pawl means on said lever, a spring urging said pawl means into engagementl with said ratchet wheel and said pawl means and ratchet wheel being constructed and arranged to impart rotation to said shaft and said windlass when said lever is moved in a first direction, a strap guiding element for guiding the strap into engagement with said windlass, a cutter member rockably mounted in said strap guiding element, spring means urging said cutter member to an inactive position, stop means defining said inactive position and cooperating means on said cutter member and said lever, said cooperating means defining a normal stopping position for said lever when said lever is moved in a second direction and serving to rock said cutter member when said lever is moved past said normal stopping position.

2. A strap tensioning tool comprising gripping means for gripping an end portion of a flexible strap, a slotted Windlass for engaging another portion or" the strap, a rotatably mounted shaft supporting said Windlass, a ratchet wheel xed to said shaft, a lever pivotally mounted on said shaft, pawl means on said lever, a spring urging said pawl means into engagement with said ratchet wheel and said pawl means and said ratchet wheel being constructed and arranged to impart rotation to said shaft and said windlass when said lever is moved in a first direction, a strap guiding element for guiding the strap into engagement with the windlass, a cutter member mounted in said strap guiding member, said cutter member having a cutting edge and being rockable about an axis parallel to said cutting edge, spring means normally holding said cutter member rocked to an inactive position, an operating arm on said cutter member extending perpendicular to the axis thereof, means on said lever for engaging said operating arm when said lever is moved in a second direction, the contact between the means on said lever and said operating arm designating a normal stopping position for said lever, and said lever being movable past the normal stopping position to thereby operate said cutter member.

References Cited in the tile of this patent UNITED STATES PATENTS 876,116 Vsetecka I an. 7, 1908 1,929,347 Bustinduy et al Oct. 3, 1933 3,013,589 Jones Dec. 19, 1961 

1. A STRAP TENSIONING TOOL COMPRISING GRIPPING MEANS FOR GRIPPING AN END PORTION OF A FLEXIBLE STRAP, A SLOTTED WINDLASS FOR ENGAGING ANOTHER PORTION OF THE STRAP, A ROTATABLY MOUNTED SHAFT SUPPORTING SAID WINDLASS, A RATCHET WHEEL FIXED TO SAID SHAFT, A LEVER PIVOTALLY MOUNTED ON SAID SHAFT, PAWL MEANS ON SAID LEVER, A SPRING URGING SAID PAWL MEANS INTO ENGAGEMENT WITH SAID RATCHET WHEEL AND SAID PAWL MEANS AND RATCHET WHEEL BEING CONSTRUCTED AND ARRANGED TO IMPART ROTATION TO SAID SHAFT AND SAID WINDLASS WHEN SAID LEVER IS MOVED IN A FIRST DIRECTION, A STRAP GUIDING ELEMENT FOR GUIDING THE STRAP INTO ENGAGEMENT WITH SAID WINDLASS, A CUTTER MEMBER ROCKABLY MOUNTED IN SAID STRAP GUIDING ELEMENT, SPRING MEANS URGING SAID CUTTER MEMBER TO AN INACTIVE POSITION, STOP MEANS DEFINING SAID INACTIVE POSITION AND COOPERATING MEANS ON SAID CUTTER MEMBER AND SAID LEVER, SAID COOPERATING MEANS DEFINING A NORMAL STOPPING POSITION FOR SAID LEVER WHEN SAID LEVER IS MOVED IN A SECOND DIRECTION AND SERVING TO ROCK SAID CUTTER MEMBER WHEN SAID LEVER IS MOVED PAST SAID NORMAL STOPPING POSITION. 